The Senate Intelligence Committee is turning up the heat on Michael Flynn

The Senate Intelligence Committee said it is issuing new subpoenas for documents from two Virginia-based business entities controlled by Michael Flynn.

The move suggests the committee is turning up the heat on Flynn, who was forced to resign from his post as President Donald Trump’s national security adviser in February.

Flynn invoked his Fifth Amendment rights on Monday, in response to the committee’s subpoena for documents related to his communications with Russian operatives between 2015 and 2017. Flynn’s attorney, Robert Kelner, cited what he described as an “escalating public frenzy against” Flynn in a letter to the committee.

The committee’s ranking member, Sen. Mark Warner, said of the new subpoenas targeting businesses connected to Flynn, “A business does not have a right to take the Fifth if it’s a corporation,” The Wall Street Journal reported.

“While we recognise General Flynn’s constitutional right to invoke the Fifth Amendment, we are disappointed he has chosen to disregard the Committee’s subpoena request for documents relevant and necessary to our investigation. We will vigorously pursue General Flynn’s testimony and his production of any and all pertinent materials pursuant to the Committee’s authorities.”

Flynn has increasingly become the center of inquiries into Russia’s meddling in the 2016 US presidential election and Russia’s contacts with Trump associates. He agreed to testify before the House and Senate intelligence committees in late March in exchange for immunity from prosecution, but neither committee has agreed to that so far.

Flynn’s time at the White House lasted just 24 days. He was asked to resign February 13, with the White House saying he had misled Vice President Mike Pence about conversations he had with Russia’s ambassador to the US, Sergey Kislyak, during the transition. But Trump continued to defend him, going as far as suggesting to FBI Director James Comey the next day to drop the investigation into Flynn’s foreign contacts, according to a memo Comey wrote about the conversation cited by The New York Times. Trump fired Comey on May 9.